The carrier dynamics and time-dependent photo-physical properties in the degradation period of hybrid organic-inorganic lead halide perovskites (HOIPs) are still unclear. Here a non-contact optical pump THz probe measurement was performed to observe the long-term degradation process of 2D passivated and cesium stabilized formamidinium lead iodide perovskite (FAPbI₃) films. We find that photoconductivity and carrier mobility of the FA_0.9Cs_0.1PbI₃ film decay steadily, while these of the 2D phenylethylammonium lead iodide (PEA₂PbI₄) passivated FAPbI₃ film show an accelerated decay rate. Moreover, it’s also revealed that the localization of charge carriers increases with the transformation process from the fitted results by the Drude-Smith model. These results indicate that the stabilized effect of Cs incorporation is continuous, while the passivated effect of PEA₂PbI₄ can be weakened by the newly emerged phase boundaries. This report proposes a new perspective and sheds light on the degradation process of HOIPs.

中文翻译：

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通过光泵太赫兹探针光谱解开二维钝化和 Cs 稳定的 FAPbI ₃的降解过程

杂化有机-无机卤化铅钙钛矿（HOIP）降解期间的载流子动力学和时间依赖性光物理性质仍不清楚。这里进行了非接触式光泵太赫兹探针测量，以观察二维钝化和铯稳定的甲脒碘化铅钙钛矿 (FAPbI ₃ ) 薄膜的长期降解过程。我们发现FA的该光电导和载流子迁移_0.9铯_0.1碘化铅₃膜衰变稳步，而这些二维苯基乙基碘化铅的（PEA ₂碘化铅₄）钝化FAPbI ₃胶片显示出加速的衰减速度。此外，还揭示了电荷载流子的局部化随着 Drude-Smith 模型拟合结果的转换过程而增加。这些结果表明，Cs 掺入的稳定作用是连续的，而 PEA ₂ PbI ₄的钝化作用可以被新出现的相界削弱。该报告提出了一个新的视角，并阐明了 HOIP 的降解过程。